Model S4000CH
39
If the S4000CH receives the query without a communications error, but cannot
process the response to the master within the master’s timeout setting, then no
response is returned from the S4000CH. The master device will eventually process a
timeout condition for the query.
In order to prevent this condition from occurring,
the maximum response time for the S4000CH is 200 milliseconds. Therefore the
master’s timeout setting should be set to 200 milliseconds or greater.
If the S4000CH receives the query without a communications error, but cannot
process it due to reading or writing to a non-existent S4000CH command register,
then the S4000CH will return an exception response message informing the master of
the error.
Byte
Modbus
Range
Referenced to S4000CH
1
st
Slave Address
1-247* (Decimal)
S4000CH ID (Address)
2
nd
Function Code
83 or 86 (Hex)
MSB is set with Function Code
3
rd
Exception Code
01 - 06 (Hex)
Appropriate Exception Code
(See Below)
4
th
CRC Lo
00-FF (Hex)
CRC Lo Byte
5
th
CRC Hi
00-FF (Hex)
CRC Hi Byte
The exception response message (ref. No. 4 above) has two fields that differentiate it from a
normal response:
6.6.2 Exception
Code
Exception Code Field:
In a normal response, the S4000CH returns data and status in the
data field, which was requested in the query from the master. In an exception response, the
S4000CH returns an exception code in the data field, which describes the S4000CH
condition that caused the exception. Below is a list of exception codes that are supported by
the S4000CH:
Code
Name
Description
01
Illegal Function
The function code received in the query is not an
allowable action for the S4000CH.
02
Illegal Data Address
The data address received in the query is not an
allowable address for the S4000CH.
03
Illegal Data Value
A value contained in the query data field is not an
allowable value for the S4000CH.
04
Slave Device Failure
An unrecoverable error occurred while the
S4000CH was attempting to perform the
requested action.
05
Acknowledge
The S4000CH has accepted the request and is
processing it, but a long duration of time will be
required to do so. This response is returned to
prevent a timeout error from occurring in the
master.
06
Device Busy
The S4000CH is engaged in processing a long-
duration program command. The master should
retransmit the message later when the slave is
free.
Table 10: Exception Codes
Содержание S4000CH
Страница 2: ...Model S4000CH i This page intentionally left blank ...
Страница 10: ...Model S4000CH 2 Figure 3 Sensor Remote Installation in inches Figure 4 ARGC Remote Installation ...
Страница 22: ...Model S4000CH 14 Figure 12 S4000CH Terminal Block Locations Figure 13 Remote Junction Box Terminal Block ...