Omega Vehicle Security PTC900 manual 12-59p, +B/

		TIME DISPLAY FORMAT
	«	12-59p	12-59 23-59
ª		

Select the format in which the Real-Time Clock Time will be displayed. The format selections depict the range for the RTC Time display, and DO NOT represent the current RTC Time. When the meter is operating in the Display Mode, the RTC Time display is shown with no annunciator.

DATE DISPLAY FORMAT

«

ª +B/ sun-31

Select the format in which the Real-Time Clock Date will be displayed. The format selections depict the range for the RTC Date display, and DO NOT represent the current RTC Date. When the meter is operating in the Display Mode, the RTC Date display is indicated by the DAT annunciator.

AUTO CHANGE FOR DAYLIGHT SAVINGS TIME

	«
ª
Selecting	allows the meter to automatically adjust the RTC Time for

Daylight Savings Time. (Adjustment dates are U.S.A. standard only.) Avoid setpoints that occur during adjustment (Sundays 1 to 3 AM).

METER TYPE FOR CLOCK SYNCHRONIZATION

«

ª

Time synchronization between multiple PTC901 meters can be accomplished through a hardware interface on the Real-Time Clock option card. This RS485 type interface allows connection of up to 32 PTC901 meters in a two-wire multidrop network, at distances up to 4000 ft. (See Section 4.6, Real-Time Clock Wiring).

In a Synchronization network, one PTC901 meter is programmed as the Host

( ), while all other meters are programmed as Slaves ( ). Once every hour (at 30 min. past the hour), the Host meter outputs a time synchronization pulse onto the network. Upon receiving the synchronization pulse, each Slave meter automatically adjusts the Minutes and Seconds of its RTC Time setting to synchronize with the Host. Synchronization, using the Real-Time Clock Wiring, adjusts the Minutes and Seconds only, and does not change the Hours, AM/PM, Day or Date settings in the Slave meter's RTC.

Full-time synchronization (hours, minutes and seconds) is possible for PAXCKs that are connected in an RS485 network (RS485 Serial Option cards required). In this configuration, one meter is designated as the Serial RTC Master by setting the meter's address as 98 or 99 (see Serial Real-time Clock Addressing in Master Module 7). Every hour (at 30 min past the hour), the Serial RTC Master / Host will transmit the full time (Hours, minutes, seconds) to all meters through the RS485 serial card wiring network. The time, date, or day will also be transmitted and updated in the Slaves when changed in the programming of the Serial RTC Master. Only one meter should be configured as Master and that meter should also be configured as the Host.

	CALIBRATE REAL-TIME CLOCK
	«
ª		* NOTE: DO NOT ADJUST TRIM CAP ON RTC CARD!

The Real-Time Clock circuit uses a crystal controlled oscillator for high accuracy timekeeping. The oscillator is factory calibrated* and optimized for 25°C ambient temperature operation. Since the PTC901 is designed to operate over a wide temperature range, and since the accuracy of a crystal oscillator varies with ambient temperature, some drift in the RTC time may be observed over an extended period. This is primarily seen in high or low temperature installations. To compensate for the wide operating temperature range, a calibration or “Offset” value can be entered, which effectively slows down or speeds up the clock to maintain accurate timekeeping.

To calibrate the RTC, install the meter in its normal operating environment, and set the time based on a known accurate reference (such as the WWV broadcast or the Atomic Clock reference which is available via the internet). After 30 days of normal operation, compare the RTC time to the reference, and note the amount of time gained or lost. Refer to the tables on the next page for the proper Offset value to enter, given the amount of time drift observed.

	«	to
ª

Selecting for the parameter displays the sub-menu where the present Offset value can be viewed or changed. The tables below show the value to enter, given the amount of time gained or lost in a 30-day period.

Values 00 and 32 provide no Offset, and are not shown in the tables.

IF RTC CLOCK GAINED TIME:

USE VALUE FROM THIS TABLE

SECONDS	ENTER THIS	SECONDS	ENTER THIS
GAINED IN	OFFSET	GAINED IN	OFFSET
30 DAYS	VALUE	30 DAYS	VALUE
5	01	90	17
11	02	95	18
16	03	100	19
21	04	105	20
26	05	111	21
32	06	116	22
37	07	121	23
42	08	127	24
47	09	132	25
53	10	137	26
58	11	142	27
63	12	148	28
69	13	153	29
74	14	158	30
79	15	163	31
84	16

IF RTC CLOCK LOST TIME:

USE VALUE FROM THIS TABLE

SECONDS	ENTER THIS	SECONDS	ENTER THIS
LOST IN 30	OFFSET	LOST IN 30	OFFSET
DAYS	VALUE	DAYS	VALUE
11	33	179	49
21	34	190	50
32	35	200	51
42	36	211	52
53	37	221	53
63	38	232	54
74	39	243	55
84	40	253	56
95	41	264	57
105	42	274	58
116	43	285	59
127	44	295	60
137	45	306	61
148	46	316	62
158	47	327	63
169	48

25