Detcon RXT-320 - Manual (Page 27)

RXT-320 Wireless Modbus ™
RXT-320 Wireless IM Rev. 2.1 Page 23 of 27
Upon power up, this register is set to 0 and the RXT-320 is not in low power mode. To place a network to
sleep the controller will generate a broadcast request (Modbus™ address = 0) and do a single write (function
code 06) to register 8202 with the number of seconds the network should go to sleep. During sleep there can
be no access to any device on the network so the user will have to trade off sleep time versus getting device
updates. Once a non-zero value is written to this register on all RXT-320s, they will begin counting down
until the Sleep Time reaches zero, at which time all RXT-320s should be active again and ready for network
communication. The controller can monitor the sleep time remaining by accessing Sleep Time register on the
RXT-320 attached to it. The Modbus™ interface remains active, only the wireless network is placed in a low
power state. The value of this register can be between 0 and 65535 which allows a maximum sleep time of
18.2 hours. Removal of power will reset Sleep Time to 0.
4.2.7 Register – Control
The Control register is generally unused and should not be written to normally. Using the control register, the
RXT-320 can be reset, Modbus™ exceptions can be enabled and the Alarm Outputs 2 and 3 can be used as
indications of receive for Modbus™ or Wireless interfaces. Each bit in the control register can control a
particular function and should be read first then modify the bits needed and written back. The default state of
the register is 0. All reserved bits should always be set to a 0 when writing. The listing below shows the bit
assignments.
Bit 15: Reserved (set to 0)
Bit 14: Debug Rx Activity Status, Alarm 2 = Wireless Rx, Alarm 3 = Modbus Rx
Bit 13 – 12: Reserved (set to 0)
Bit 11: Modbus Exceptions Enabled
Bit 10 – 08: Reserved (set to 0)
Bit 07: Reset the microcontroller and wireless radio
Bit 06: Reset the microcontroller
Bit 05 – 00: Reserved (set to 0)
4.2.8 Register – Status
This register contains status of the RXT-320 and some of the bits have already been covered in the battery
description. These default to 0 upon reset. The bit assignment and description are given below.
Bit 15 – 08: Reserved (set to 0)
Bit 07: I
2
C Fault on last read of Modbus Address Switch (Rotary Switch on Term Board)
Bit 06: Modbus Address Switch Detected (Always set to a 1 when address set)
Bit 05: I2C Fault on last read of Battery Status
Bit 04: Battery Detected
Bit 03: Alarm Station address detected – second set of Alarm Output registers available
Bit 02: Slave RXT-320
Bit 01: Master RXT-320 – controller attached to Modbus™ interface
Bit 00: Reserved (set to 0)
4.2.9 Register – Address Switch
The rotary switch on the Model 100 Termination board provides the Modbus™ address through the I 2 C
interface. There is both an Address Switch Detect and Fault bit defined in the status register. The rotary
switch is read approximately every 5 seconds and the Fault bit is set if the last read failed. Register 8207 (I2C
Switch Read Fails) will increment by 4 each time there is a failure since there are 4 attempts before declaring
failure. This register can be cleared by writing a 0 to it at any point.