Digital Output Packed Bit Variables - Black Box CRCW-12 User Manual

Cold row chilled water (cw)

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Chapter 4: E2 Controller

4.9.7 Digital Output Packed Bit Variables

The R/W BMS variables fall into two categories. Variables like the temperature setpoint are permanent. As permanent variables,

they retain their value regardless of power loss or BMS communications failure. The controller's flash memory is limited to one

million write cycles for permanent variables. The other category is the integer and digital variables that start with "BMS." These

are expected to be changed frequently and require that the BMS is active when changing them. All BMS variables require that the

BMS "keep alive" parameter (Variable 100) changes between 1 and 2 within a 10-minute span. The general procedure is to set

up variables like the BMS low fan speed and then write a 1 to the BMS "keep alive" address. If the controller does not see a 2

written to the BMS "keep alive" address within 10 minutes, all the BMS variables will revert to their previous values.

Page 106

Table 4-35. Digital Output Packed Bit Variables.

Bit

Digital Outputs 1

Global alarm

Custom alarm 1

Master fan enable

DX1 enable

DX1 liquid line solenoid

Humidifier enable

Dual power output A

Dual power output B

Pump enable

Custom alarm 2

Custom alarm 3

Reserved

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Digital Outputs 2

Reserved

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