Modbus – Bryant 548J User Manual

Page 46

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Table 18 – Manufacture Date

When troubleshooting, you may need to know a control module’s manufacture date.

Obtain the manufacture date from

a...

Notes

Module status report (modstat)

To obtain a modstat with BACview

6

:

1. Press Function (FN) key and hold.

2. Then press period (.)

3. Release both buttons.

The report shows the date under

Main board hardware.

Sticker on the back of the main control

module board

“Serial No: RMPYMxxxxN”

(Bar Coded & Typed Number)

The serial numbers are unique and contain embedded information:

“RMP”

---

These first three digits are unique to RTU---MP and are used as an identifier.

“YM”

---

These two digits identify the last digit of the year and month (in hex, A=10/Oct)

of manufacture. “74” would represent a date of manufacture of “April 2007”.

xxxx”

---

These four digits represent the sequential number of units produced for a given

product for the mentioned manufacturing time period.

“N”

---

This final digit represents the decade and toggles between “N” and “M” every

ten years.

Table 19 – Basic Protocol Troubleshooting

Problem

Possible cause

Corrective action

No communication with 3rd

party vendor

Incorrect settings on SW1, SW2 and SW3

Verify and correct switch settings. Cycle

power to RTU---MP after changing switch

settings.

RS485 Port has no voltage output

(check with RTU---MP disconnected from RS485

communication bus):

• Bacnet @ 9600/19.2K --- .01 to .045vdc

• Bacnet @ 38.4K --- .06 to .09vdc

• Bacnet @ 76.8K --- .1vdc

• Modbus @ 9600 --- 76.8K --- .124vdc

• N2 @ 9600 --- .124vdc

• LON @ 9600 --- .124vdc

Verify RTU---MP has correct power supply.

Possible bad driver on board.

Check RS485 bus for external voltage,

shorts or grounding before reconnecting

to the bus.

Verify devices are daisy chained and repeaters and bias

terminators are correctly installed.

Check 3rd party vendor RS485

communication wiring guidelines and

troubleshooting procedures.

Table 20 – Modbus Exception Codes that May be

Returned From This Controller

CODE

NAME

MEANING

01

Illegal Function

The Modbus function code used

in the query is not supported by

the controller.

02

Illegal Data Address

The register address used in the

query is not supported by the

controller.

04

Slave Device Failure

The Modbus Master has

attempted to write to a

non---existent register or a

read---only register in the

controller.

Modbus

1. Verify that the BAS and controller are both set to

speak the Modbus RTU protocol. The protocol of the

controller is set via SW3 (switches 3, 4, 5, and 6).

The protocol can also be verified by getting a Modstat

of the controller through the BACview. Hit the “FN”

key and the “.” key at the same time to pull up a

Modstat. Scroll to the bottom of the page and there is

a section entitled “Network Communications.” The

active protocol and baud rate will be shown in this

section.

2. Verify that the BAS and controller are set for the

same baud rate. The baud rate of the controller is set

via SW3 (switches 1 and 2). The baud rate can also

be verified via the BACview by obtaining a Modstat

(see above).

3. Verify that the BAS is configured to speak 2--wire

EIA--485 to the controller. The BAS may have to

configure jumper or DIP switches on their end.

4. Verify that the BAS and the controller have the same

communication settings (8 data bits, No Parity, and 1

stop bit).

5. Verify that the controller has a unique Modbus slave

address. The controller’s Modbus slave address is set

by its rotary address switches.

6. Verify that the BAS is using the proper Modbus

function codes to access data from our controller.

Supported function codes are shown above.

7. Verify proper wiring between the BAS and the

controller.

8. Verify that the BAS is reading or writing to the proper

Modbus register numbers on the controller. Download

the latest points list for the controller to verify.

9. Verify that the BAS is sending his requests to the

proper slave address of our controller.

NOTE: See RTU--MP 3rd Party Integration Guide (or

alternatively Form 48--50H--T--1T, Appendix) for Modbus
Protocol Conformance Statement.

548J

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