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PCHS/TPCHS SERIES Quick-Set PowerCassette®
INSTALLATION & OPERATING MANUAL
Manual No. tpchs-2
pchs-tpchs-man-rev2-1214.indd
OPERATION AND FUNCTIONS
Digital Functions
Digital status functions are provided by a PCF8574 8-bit
I/O port device. When this device is read by the serial
bus controller a single 8-bit word provides the following
information:
BIT FUNCTION
GOOD
STATE MEANING
0
Input Power Fail
0
Provides 10ms warning of input
supply failure.
1
1
Output Power
Good
1
V1, 2 and 3 are within specified
limits.
2
Temperature
Warning
1
Internal temperature exceeds
60°C.
3
Fan #1 Good
1
Fan running at >80% nominal
speed.
4
Fan #2 Good
1
Fan running at >80% nominal
speed.
5
Fan #3 Good
1
Fan running at >80% nominal
speed.
6
-
-
-
7
Temperature
Alarm
1
Internal temperature exceeds
70°C, unit switched off.
Note 1: AC input versions only. Requires use of Interrupt line to
provide warning time specified.
PCF8574 slave address
BIT
7
6
5
4
3
2
1
0
VALUE
0
1
0
0
0
A1
A0
R/W
Note: The PCF8574 must only be used in the READ mode.
EEPROM Functions
The EEPROM is a 2048 bit (256 byte) device which is
preprogrammed at the factory with the following data:
ADDRESS
RANGE
DATA
Note:
Data is organized such that
each field of data can be
accessed by a page read
(16 bytes).
0-15
Model Number
16-31
Manufacturing Part Number
32-47
Serial Number
48-63
Modification Level
64-79
Manufacturer
80-95
Country of Manufacture
96-102
Switch Setting
103-255
Not Used
EEPROM slave address
BIT
7
6
5
4
3
2
1
0
VALUE
1
0
1
0
0
A1
A0
R/W
Note: Customers may specify to special order other data which they
may require.
Analogue Functions
Analogue status functions are provided by two PCF8591
4-channel 8-bit A/D converter devices. When these devices
are read by the serial bus controller a single 8-bit word
provides the following information:
Device: U208
Device: U215
A/D FUNCTION A/D FUNCTION A/D FUNCTION A/D FUNCTION
1
V1 voltage
3
V3 voltage
1
V1 current
3
V3 current
2
V2 voltage
4
Not Used
2
V2 current
4
Not Used
slave address
BIT
7
6
5
4
3
2
1
0
DEVICE
VALUE
1
0
0
1
1
A1
A0
R/W
U208
VALUE
1
0
0
1
0
A1
A0
R/W
U209
The PCF8591 devices initially require a control byte (04
Hex) to be written to the configuration register. This control
byte sets the device so that on each successive read the
data from the next A/D is read. Note that on each read a
conversion is started for a particular channel and the result
will be read from the previous channel, thus the first result
from a sequence of reads should always be discarded.
A/D converter scaling
To obtain a correct voltage or current measurement it is
necessary to employ both scaling and offset factors in the
controlling software. Note that all voltage measurements
are made inside the PSU module, before the ‘ORing’
diodes, and are typically 0.5V higher than the actual
module output voltage.
The following calculation should be employed:
Value = (byte read x scaling factor) + offset
Output Voltage Scaling Tolerance Offset
1.8/2.5V
0.012
±2%
0
V1, V2 Voltage
(U208 A/D 1 & 2)
3.3V
0.015
±2%
0
5.0V
0.023
±2%
0
12.0V
0.0547
±2%
0
V3 Voltage (U208 A/D 3)
15.0V
0.0686
±2%
0
1.8/2.5/3.3/5.0V
0.37
±10%
0
V1 Current (U215 A/D 1)
1.8/2.5/3.3/5.0V
0.43
±10%
0
V2 Current (U215 A/D 2)
12.0/15.0V
0.068
±5%
0
V3 Current (U215 A/D 3)
Temperature Measurement Functions
The internal temperature of the unit is measured using a
MAX6633. This device provides a 12-bit measurement at
a resolution of 0.0625°C.
MAX6633 slave address
BIT
7
6
5
4
3
2
1
0
VALUE
1
0
0
0
0
A1
A0
0
Note: The MAX6633 must only be used in the READ mode.
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