Red Lion PAXCDC4 User Manual

Finger Hold

Finger

Hold

Serial

Communications

Card

Setpoint Output Card

Alignment

Slots

Connectors

Main Circuit Board

Analog Output

Real-Time

Clock Card

ANALOG OUTPUT OR REAL-TIME CLOCK CARD

SETPOINT OUTPUT CARD LABEL

SERIAL OUTPUT CARD LABEL

MAIN

LABEL

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MODEL PAXCDC -MODBUS OUTPUT OPTION CARD

DESCRIPTION

This product bulletin covers the MODBUS Communication Card for the PAX

Meters. The card will allow the PAX Meter to transmit Display Values,

Setpoints and Reset Values via and ASCII modes.

Bulletin No. PAXCDC4-F Drawing No. LP0502 Released 09/09

MODBUS RS485 communication, in the RTU

INSTALLING AN OPTION CARD

Caution: The option and main circuit cards contain static sensitive components. Before handling the cards, dischar ge static charges from your body by touching a grounded bare metal object. Ideally, handle the cards at a static controlled clean workstation. Also, only handle the cards by the edges. Dirt, oil or other contaminants that may contact the cards can adversely affect circuit operation.

Warning: Exposed line voltage exists on the circuit boards. Remove all power to the meter AND load circuits before accessing the unit.

1. Remove the main assembly from the rear of the case. Squeeze the finger holds on the rear cover, or use a small scewdriver to depress the side latches to release it from the case. It is not necessary to separate the rear cover from the main circuit card.

2. Locate the option card connector for the type of option card to be installed. Hold the unit by the rear connector, not the display board, when installing an option card.

3. Install the option card by aligning the option card connector with the slot in the rear cover. The cards are keyed by position with different main board connector locations. Be sure the connector is fully engaged and the tab on the option card rests in the alignment slot on the display board.

4. Slide the assembly back into the case. Be sure the rear cover latches fully into the case.

5. Apply the option card label to the bottom side of the meter. Do not cover the vents on the top surface of the meter. The surface of the case must be clean for the label to adhere properly. Apply the label to the area designated by the large case label.

6. See manual for wiring connections and programming procedures.

TOP VIEW

MODBUS SPECIFICATIONS

1. Type: RS485; RTU and ASCII MODBUS modes

2. Isolation To Sensor & User Input Commons: 500 Vrms for 1 minute.

Working Voltage: 50 V. Not isolated from all other commons.

3. Baud Rates: 300 to 38400.

4. Data: 7/8 bits

5. Parity: No, Odd, or Even

6. Addresses: 1 to 247.

7. Transmit Delay: Programmable; See Transmit Delay explanation.

ORDERING INFORMATION

MODEL DESCRIPTION PART NUMBER

PAXCDC

PAX MODBUS Output Card PAX MODBUS Output Card with RJ11 Connector

PAXCDC40 PAXCDC4C

B(-)

33K

+5V

Transmit Enable

PAX METER

RECEIVING DEVICE

(+)

COMM. *

OPTIONAL

RS485 COMMUNICATIONS

The RS485 communication standard allows the connection of up to 32 devices on a single pair of wires, distances up to 4,000 ft. and data rates as high as 10M baud (the PAX is limited to 19.2k baud). The same pair of wires is used to both transmit and receive data. RS485 is therefore always half-duplex, that is, data cannot be received and transmitted simultaneously.

Transmit Enable

Terminal Block Connection Figure

Not used

PAX CONNECTOR

Not used

COMM

B-

A+

3542

Extended Comms Connection Figure

PAX METER

+5V

33K

Not used

RECEIVING DEVICE

(+)

COMM.

OPTIONAL

SERIAL SET-UP DIP SWITCH OPERATION

Serial port configuration is accomplished through two banks of DIP switches on the MODBUS card. The bank of 8 switches sets the Unit Address, the bank of 7 switches sets the Serial port parameters (ASCII/RTU, 7/8 bits, Parity, and Baud rate). Changes to the switch settings are only detected on power-up of the unit. After changing a switch setting, power to the unit must be cycled for the new switch setting to take effect.

BIT

(+128)

(+64)

(+32)

(+16)

(+8)

(+4)

(+2)

WEIGHTS

12345678 1234567

Both unit address and serial set-up are set via DIP switches on the option card. See the DIP switch setting table for more details on these DIP switches.

For the Unit Address bank, the high order bit is switch 1, and the ON position is a ‘1’, the OFF position is a ‘0’. Legal unit addresses are 1 to 247. When a Unit Address of 0 is selected, the card responds to Unit Address 1. When a Unit Address of 248 through 255 is selected, the card responds to Unit Address 247.

(+1)

SERIAL SET-UPUNIT ADDRESS

MODBUS

For the serial bank, the following settings apply:

SWITCH SETTINGS AVAILABLE

5 Baud Rate 6 Baud Rate 7 Baud Rate



(See Baud Rate



Switch Selections)



BAUD RATE SWITCH SELECTIONS

5 6 7

38400: 19200:

9600: 4800: 2400: 1200:

ON ON ON ON ON OFF ON OFF ON

ON OFF OFF OFF ON ON OFF ON OFF OFF OFF ON

600:

OFF OFF OFF

300:

FACTORY SETTINGS

RTU1 OFF: ASCII ON: RTU

8 Bits2 OFF: 7 Bits ON: 8 Bits

No Parity3 OFF: None ON: Parity

OFF4 OFF: Even ON: Odd

9600

MODBUS SUPPORTED FUNCTION CODES

COIL FUNCTIONS

FC01: Read Coils FC05: Force Single Coil, FC15: Force Multiple Coils.

1. Valid coil addresses are 1-49.

2. Block starting point can not exceed coil 49.

HOLD REGISTER FUNCTIONS

FC03: Read Holding Registers. FC06: Preset Single Register, FC16: Preset Multiple Registers.

1. Valid register address are 40001 – 40039, 40041, 40042, 41001 – 41010.

2. Up to 16 registers can be requested at one time.

3. Block starting point can not exceed the register boundaries.

4. Holding registers are a mirror of Input registers (FC04).

5. Unused registers will return a value of HEX <8000>.

6. If a register is implemented, but does not exist for a particular unit configuration (such as SP3, SP4) a value of HEX <0000> will be returned.

7. Registers 41001 – 41010 contain the slave ID. See FC17.

8. Broadcast write is supported for FC06 & FC16. Register writes using address “0” will be recognized by the MODBUS card, regardless of address DIP switch setting.

PAX MANUAL MODE DESCRIPTION

(CSR) Control Status Register [40021]

The Control Status Register is used to directly control the meter’s outputs (setpoints and analog output), or view the state of the setpoint outputs and the status of the temperature sensor (PAXT only). The register is bit mapped with each bit position within the register assigned to a particular control function. The control functions are invoked by writing to each bit position. The bit position definitions are:

bit 1: SP2 Output bit 2: SP3 Output bit 3: SP4 Output bit 4: Manual Mode

0 = automatic mode 1 = manual mode

In Manual Mode, the setpoint outputs are defined by the values written to bits b0, b1, b2, b3; and the analog output is defined by the value written to the AOR. Internal control of these outputs is then overridden. In automatic mode, the setpoint outputs can only be reset off.



0 = output off



1 = output on



bit 5: Always stays 0, even if 1 is sent.bit 0: SP1 Output bit 6: Sensor Status (PAXT only)

0 = sensor normal 1 = sensor fail

bit 7: Always stays 0, even if 1 is sent.

OTHER SUPPORTED FUNCTIONS

FC04:

Returns the same values as FC03, except the register number starts with “3”

(Ex: Pax Input Hi is 30001)

FC08 – Fetch Comm. Event Counter.

The MODBUS response breaks down as follows:

“:010804”<TOT HI><TOT LO><GOOD HI><GOOD LO>XX<CR><LF>

The “TOT HI” and “TOT LO” values are the total number of messages that were received, that started with the card’s address. The “GOOD HI” and “GOOD LO” are “good” messages (correct address, parity, and checksum). The values are reset on power up and every time the FC08 function is requested.

FC17 - Report Slave ID.

The following is sent upon FC17 request:

Unit Address, 17 (FC code), RLC-PAX(I or ?) 00?0, 0100 (for code version

1.00), 16 (number of read supported registers), 16 (number of write supported registers), 00 (number of registers available for GUID/Scratch pad memory), checksum of the string.

The following is the HEX of a PAXI (with unit address of 247):

:<F7><11><14><52><4C><43><2D><50><41><58><49><30><30><3F> <30><01><00><00><10><00><10><00><00><XX><CR><LF>

XX is the LRC Checksum

(SOR) Setpoint Output Register [40038] (PAXI/DR/CK/TM)

This register is used to view or change the states of the setpoint outputs. Reading from this register will show the present state of all the setpoint outputs. A “0” in the setpoint location means the output is inactive and a “1” means the output is active.

In Automatic Mode (See MMR Description), the meter controls the setpoint output state. In Manual Mode, writing to this register will change the output state. The bit position definitions are:

bit 0: SP1 bit 1: SP2 bit 2: SP3 bit 3: SP4

Examples:

1. Turn all outputs on:

Value to write to holding register 40038: 000Fh.

2. Turn outputs 1, 3 on:

Value to write to holding register 40038: 0005h.

3. Turn all outputs off:

Value to write to holding register 40038: 0000h.



0 = Output off



1 = Output on



(MMR) Auto/Manual Mode Register [40036] (PAXI/DR/CK/TM)

This register sets the controlling mode for the outputs. In Auto Mode (0) the meter controls the setpoint output. In Manual Mode (1) the outputs are defined by the registers SOR. When transferring from auto mode to manual mode, the meter holds the last output value (until the register is changed by a write). Each output may be independently changed to auto or manual. Select values to place in manual mode by writing appropriate value to holding register 40036. The bit position definitions are:

PAXI/PAXDR

bit 0: Analog Output bit 1: SP4 bit 2: SP3 bit 3: SP2 bit 4: SP1

Examples:

1. Select manual mode for all outputs (PAX):

Value to write to holding register 40021: 0010h

2. Select manual mode for all outputs and AOR (PAXI, PAXDR):

Value to write to holding register 40036: 001Fh



0 = Auto Mode



1 = Manual Mode



PAXCK/PAXTM

bit 0: SP4 bit 1: SP3 bit 2: SP2 bit 3: SP1



0 = Auto Mode



1 = Manual Mode



(AOR) Analog Output Register (Not Applicable to P AXCK/TM)

The Analog Output Register controls the analog output of the meter. The manual mode must first be engaged by setting bit 4 of the CSR (PAX) or bit 0 of the MMR (P AXI/DR). The range of values of this register is 0 to 4095, which corresponds to 0 mA, 0 V and 20 mA, 10 V; respectively. If a value larger than 4095 is written to the AOR register, 4095 will be loaded. The table lists correspondence of the output signal with the register value.

0 0.0000.000

1 0.00250.005 2047 5.00010.000 4094 9.997519.995 4095 10.00020.000

Writing to this register while the meter is in the manual mode causes the output signal to update immediately. While in the automatic mode, this register may be written to, but the output will not update until the meter is placed in manual mode.

Examples:

1. Set output to full scale:

Value to write to holding register 40020 (PAX) or 40037 (PAXI/DR): 0FFFh

(4095).

2. Set output to zero scale: Value to write to holding register 40020 (PAX) or 40037 (P AXI/DR): 0000h (0).

Output Signal*

I (mA)

V (V)

*Due to the absolute accuracy rating and resolution of the output card, the actual output signal may differ 0.15% FS from the table values. The output signal corresponds to the range selected (20 mA or 10 V).

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